This application is a 371 of PCT/FR99/01129, May 11, 1999.
The present invention relates to novel water-soluble furylphosphines.
It also relates to organometallic complexes comprising these furylphosphines and to the use of such complexes.
It also relates to the process for the preparation of the water-soluble furylphosphines.
Unsubstituted trifurylphosphines are described in an article by V. Farina and B. Krishnan published in the Journal of the American Chemical Society, 1991, 113, pages 9585-9595. According to this article, systems comprising these trifurylphosphines exhibits a notable catalytic activity.
The prior art does not disclose water-soluble furylphosphines such as those forming the subject-matter of the present invention.
The novel water-soluble furylphosphines correspond to the general formula (I): 
in which:
n represents an integer from 1 to 3,
at least one R2 radical represents a hydrophilic group, such as
xe2x80x94SO2M, xe2x80x94SO3M, xe2x80x94CO2M or xe2x80x94PO3M, M representing an inorganic or organic cationic residue chosen from a proton, cations derived from alkali metals or alkaline earth metals, ammonium cations xe2x80x94N(R)4, in the formula of which the R symbols, which are identical or different, represents a hydrogen atom or an alkyl radical having from 1 to 12 carbon atoms, or other cations derived from metals having furylsulphinic acid. furylcarboxylic acid, furylsulphonic acid or furylphosphonic acid salts which are soluble in water.
N(R)3X, in the formula of which the R symbols, which are identical or different, represent a hydrogen atom or an alkyl radical having from 1 to 12 carbon atoms and X represents an organic or inorganic anion.
xe2x80x94OH,
R1 represents a hydrophilic group as defined for R2 or an alkyl or alkoxy group having 1 to 12 carbon atoms, a halogen atom, a nitrile group or a haloalkyl group having 1 to 12 carbon atoms,
m represents 1 or 2,
p represents an integer from 0 to 3,
when m is equal to 2, an R2 radical can represent an alkyl or alkoxy group having 1 to 12 carbon atoms, a halogen atom, a nitrile group or a haloalkyl group having 1 to 12 carbon atoms.
The term xe2x80x9cwater-solublexe2x80x9d or the expression xe2x80x9csoluble in waterxe2x80x9d is understood to mean, in the present text, a compound soluble to at least 0.01 g per liter of water.
The water-soluble furylphosphines of the invention are generally compounds of general formula (I) in which:
n represents an integer from 1 to 3,
R2 represents a hydrophilic group, such as xe2x80x94SO2M, xe2x80x94SO3M, xe2x80x94CO2M or xe2x80x94PO3M, M representing an inorganic or organic cationic residue chosen from a proton, cations derived from alkali metals or alkaline earth metals, ammonium cations xe2x80x94N(R)4, in the formula of which the R symbols, which are identical or different, represent a hydrogen atom or an alkyl radical having from 1 to 4 carbon atoms, or other cations derived from metals having furylsulphinic acid, furylcarboxylic acid, furylsulphonic acid or furylphosphonic acid salts which are soluble in water,
m represents 1 or 2,
R1 represents a hydrophilic group as defined for R2 or an xe2x80x94N(R)3X substituent, in the formula of which the R symbols, which are identical or different, represent a hydrogen atom or an alkyl radical having from 1 to 4 carbon atoms and X represents an organic or inorganic anion, an xe2x80x94OH substituent, an alkyl or alkoxy substituent having 1 to 4 carbon atoms, a halogen atom, a nitrile group or a trifluoroalkyl group,
p represents an integer from 0 to 2.
Another subject-matter of the present invention is the preparation of the novel water-soluble furylphosphines. This preparation is generally carried out starting with a precursor, such as diphenylfurylphosphine or phenyldifurylphosphine or trifurylphosphine, which is unsubstituted by hydrophilic groups. In consists in introducing R2 hydrophilic groups onto the furyl rings and, optionally, R1 groups onto the phenyl rings.
For example, furylphoshphines of formula (I) can thus generally be prepared by coupling an organolithium compound, the organic part of which corresponds to a compound of general formula (I) which does not comprise R2 substituents and which is bonded to the lithium atom via its furyl ring or rings, to the electrophilic centre of an R2 precursor, such as, for example, sulphur dioxide, carbon dioxide, alkyl chlorophosphates, pyridine sulphonates or trialkylamine sulphonates.
The organolithium compound is itself obtained by the action of a lithiated base (for example butyllithium) on the precursor furylphosphine.
Reference may be made, for the preparation of the precursor furylphosphines, to, for example, the article by A. J. Zapata and A. C. Rodon in Org. Prep. Proced. Int., 27, 5 (1995), pages 567 et seq.
Water-soluble furylphosphines make it possible to prepare organometallic complexes which comprise at least one water-soluble furylphosphine of formula (I) and at least one metal.
The metals which can be completed by water-soluble furylphosphines are generally all the transition metals from Groups1b, 2b, 3b, 4b, 5b, 6b, 7b and 8 of the Periodic Classification of the Elements as published in xe2x80x9cHandbook of Chemistry and Physics, 51st Edition (1970-1971)xe2x80x9d of The Chemical Rubber Company.
Mention may more particularly be made, among these metals, of the metals which can be used as catalysts of chemical reactions. Thus, mention may, of non-limiting examples, of nickel, cobalt, iron, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, silver, gold, zinc, cadmium or mercury.
The organometallic complexes comprising the water-soluble furylphosphines can be prepared by bringing a solution of a compound of the chosen metal into contact with an aqueous solution of the water-soluble furylphosphine of formula (I).
The compound of the metal can be dissolved in water or in an organic solvent, it being possible for the said organic solvent itself to be miscible or immiscible with water.
The metal, in the compound employed, can either be at the degree of oxidation which it will have in the organometallic complex or at a higher degree of oxidation.
It may be indicated, by way of examples, that, in the organometallic complexes of the invention, rhodium is at the degree of oxidation (I), ruthenium at the degree of oxidation (II), platinum at the degree of oxidation (I), palladium at the degree of oxidation (II), osmium at the degree of oxidation (O), iridium at the degree of oxidation (O) and nickel at the degree of oxidation (O).
If during the preparation of the organometallic complex, the metal is employed at a higher degree of oxidation, it will have to be reduced in situ.
Organometallic complexes comprising the water-soluble furylphoshphines of formula (I) can be used as catalysts of chemical reactions.
In aqueous two-phase catalysis, the water-soluble furylphosphines benefit from the synergy between the natural hydrophilicity of the furyl ring and that of the R2 radical or radical. They achieve very high solubility values in water.
Mention maybe made, as chemical reactions which can be catalysed by organometallic complexes comprising the water-soluble furylphosphines of formula (I), of, for example the hydroformylation and the hydrocarbonylation of olefins in the presence of rhodium complexes, the hydrogenation of olefins, aldehydes, acids, enamides and nitroaromatic compounds in the presence of ruthenium, rhodium, platinum or palladium complexes, the terrorization of dienes, the isomerization of olefins, the dimerization of ethylene or of acrylonitrile, the hydrocyanation of olefins in the presence of nickel complexes, the synthesis of furan in the presence of ruthenium complexes, the metathesis of olefins in the presence of ruthenium complexes, the polymerization of acrylates in the presence of nickel complexes or carbon-carbon coupling reactions, such as, for example, the Heck or Suzuki reaction, in the presence of nickel or palladium complexes.
The compounds of the invention are in particular of use in the isomerization reaction of nitriles obtained by hydrocyanation of a diene and more particularly the isomerization of 2-methyl-3-butenenitrile to 3-pentenenitrile. This reaction has great industrial importance in the process for the manufacture of adiponitrile. The latter is a major synthetic intermediate in, in particular, the manufacture of monomers for polyamides, such as caprolactam or hexamethylenediamine.
The examples which follow illustrate the invention.